Source: http://www.history.navy.mil/faqs/faq2-1.htm http://en.wikipedia.org/wiki/F4F_Wildcat
The movie begins in in the summer of 1942. Aircraft and Markings are incorrect nad so are the types of fighers. The markings on the planes as shown were not adopted until September 14,1943 and continued through January 1947. Further, the movie shows Hellcats being operating out of Henderson field in 1942. In reality, the Hellcat went into combat in the early fall of 1943, with its first major action in a raid against Rabaul harbor on New Britain on 5 November 1943. This movie outlines the Cactus Air Force; the ensemble of allied air power assigned to the island of Guadalcanal from August 1942 until December 1942 during the early stages of the Guadalcanal Campaign, particularly those operating from Henderson Field. The term "Cactus" comes from the Allied code name for the island. It was not until 1943 that more advanced naval fighters, the F6F Hellcat and F4U Corsair, capable of taking on the Zero on more even terms reached the South Pacific theatre. The newer Hellcats were likely used because the movie was made in 1951.